The present invention relates to novel 2-(p-sulphophenyl) amino-1,3,5-triazine derivatives and to their use in dyeing animal protein fibers (such as wool, cony hair, camel hair and natural silk) and their textile fabric as a cationic dye auxiliary agent.
For a long time it has been known to use acid dyes (including weak acid dyes), acid mordant dyes or reactive dyes to dye animal protein fibers, such as wool, natural silk and so on. For example, CN1040643A disclosed that acid mordant dyes were used to dye textile fabric, that mordant NaCN was used for the mordant dyeing process, and that compound of formula [10] was used to partially replace NaCN for the mordant dyeing process. In CN1035536A, it was mentioned that acid mordant was used to dye protein fibers with the addition of mixed chlorinates of rare elements, formic acid, etc. 
Up to now, the methods of dyeing animal protein fibers by use of acid dyes (including weak acid dyes), acid mordant dyes or reactive dyes still exhibit the following shortcomings. 1) The method cannot achieve high dyeing quality, i.e., the color is not bright enough and the color fastness is not sufficient. 2) In the dyeing and finishing process, use of a great amount of strong acids and hypertoxic chemicals (for example, NaCN) heavily impairs the environment and human health. 3) During the dyeing and finishing process, the cost increases by using varied dye auxiliary agents, such as penetrating agents, diffusing agents, softeners and so on, which, at the same time, cause heavy environmental pollution.
The cationic dyes developed afterwards are especially for acrylic fibers. The dyes are bonded together with fibers mainly through ionic bonding and/or covalent bonding. Although cationic dyes have a complete range of color spectra, a satisfactory variety of color, and bright color and high color fastness, they could not be used to dye and finish animal protein fibers.
Due to the aforementioned reasons, the stage-dyeing process should be used for dyeing blended yarn or blended fabric which contains animal protein fiber and synthetic fiber by using different kinds of dyes, i.e., dyeing the synthetic fiber and then dyeing the animal protein fiber, or dyeing the animal protein fiber first and then dyeing the synthetic fiber. The process needs a long time to complete by using a large amount of dyes with a subsequent high cost.
The object of the present invention is to provide a cationic dye auxiliary agent so that it is possible to use cationic dyes for dyeing and finishing animal protein fibers.
The present invention further provides a process for preparing the cationic dye auxiliary agent.
The invention further provides the application of such a cationic dye auxiliary agent when cationic dyestuffs are used to dye and finish animal protein fibers.
This invention also provides a process for dyeing and finishing animal protein fibers by using cationic dyestuffs through the cationic dye auxiliary agent.
The objects of the invention are achieved by providing novel 2-(p-sulphophenyl) amino-1,3,5-triazine derivatives of formula [1] and salts thereof, preferably their sodium salts 
wherein R1, represents halogen, preferably Cl, F, R2, is xcex1- or xcex2-naphthylamino, xcex1- or xcex2-naphthoxy.
The cationic dye auxiliary agent according to the present invention can be selected from the group of the following compounds (a)xcx9c(g) and sodium salt thereof: 
This invention further provides the method for synthesizing the above-described 2-(p-sulphophenyl) amino-1,3,5-triazine derivatives.
The compound of formula [1] can be synthesized according to the following procedures: 
In the above procedures, the compounds of formula [1] are prepared with cyanuric trihalide [3], p-aminobenzene sulfonic acid [2] (or salt thereof) and amino-naphthalene (or naphthol) HR3, as raw materials by a two-step reaction.
Reaction (1): Cyanuric trihalide as formula [3] is dissolved into ice water in a reaction vessel, then p-aminobenzene sulfonic acid as formula [2] or its salt is slowly added into the solution and the reaction is initiated. The temperature is controlled at xe2x88x923xcx9c10xc2x0 C., and the pressure is between 0 and 0.05 MPa. Then the catalyst, i. e., a mixed solution of sodium hydroxide and phosphoric acid, is added into the reaction solution. The reaction is sustained for 3xcx9c5 hrs. When the pH value of the reaction solution exceeds 5 and the amount of free amine is less than 0.8%, the intermediate as formula [4] is obtained.
Reaction (2): The intermediate as formula [4] is moved into another reaction vessel, then a solution of compound HR2 (xcex1- or xcex2-naphthylamino, or xcex1- or xcex2-naphtol) as well as a catalyst, i. e., a mixed solution of sodium hydroxide and phosphoric acid, are added into the same vessel. The reaction is sustained for 4xcx9c5 hrs. at a temperature of 15xcx9c50xc2x0 C., under a pressure of 0xcx9c0 03 MPa, with pH value of 5xcx9c10. When the pH value is adjusted to around 7 by using acetic acid, the compound as formula [1] is finally obtained through discharging, filtering, drying and grinding.
In the above synthetic processes, molar ratios of the three raw materials are controlled within the range as: cyanuric trihalide: p-aminobenzene sulfonic acid or its salt: naphthylamino (or naphthol)=1.0: (1.10xcx9c1.3): (1.0-1.25). For reaction (1), the yield of the intermediate as formula [4] is between 87% and 92%, and the yield of product of formula [1] for reaction (2) is 91%-97%.
There is an essential difference between the dye agent according to the present invention and other ones used in the prior art in the dyeing and finishing industry. The dye auxiliary agent used in the prior art only plays a certain role as a dyeing promoter, but does not participate in the chemical reaction of the molecular chain. However, the dye auxiliary agent according to the present invention participates in the chemical reaction of the molecular chain, i.e., one end group of molecules of the dye auxiliary agent chemically reacts with the fiber molecules and the other group reacts with the cationic dye molecules, thus the cationic dye is firmly bonded to the fiber molecule to achieve coloration. The compound according to the present invention plays a role as a link arm. The cationic dye, which formerly could not bind with the protein fiber, thus bonds to the protein fiber by the aid of said link arm.
The present invention further provides the application of the compounds as formula [1] as a cationic dye auxiliary agent when cationic dyestuffs are used for dyeing and finishing animal protein fiber or its fabric as well as blended yarn or its fabric containing animal protein fiber. Herein, said animal protein fibers are such hairs as wool, cashmere, cony hair, and camel hair, as well as natural silk. Blended yarn means a combination of the animal protein fiber with synthetic fiber, such as wool combining with acrylic fiber, or combining natural silk with rayon. Said fiber means top or yarn.
The method of dyeing hairs (such as wool, cony hair, camel hair, cashmere) or its yarn or fabric by using cationic dyes according to the present invention comprises the steps of:
1) circulating a bath containing said fibers or fabrics with water at a temperature of 20xcx9c30xc2x0 C., in which the bath ratio is between 1:30 and 1:50, and the pH value is adjusted to 3xcx9c6; adding the compound as formula [1] as a cationic dyeing auxiliary agent in an amount of 1xcx9c8 wt. % on the basis of the total weight of the fibers or fabrics, then circulating the bath for 15xcx9c20 minutes;
2) introducing cationic dyes into the bath in an amount of 0.01xcx9c3 wt. % on the basis of the weight of the fibers or fabrics; after cycling the bath with a pump for 10xcx9c15 minutes at ambient temperature, heating the bath to 98xcx9c100xc2x0 C. at a rate of 1xcx9c2xc2x0 C./min, then boiling the bath for 40xcx9c60 minutes; cooling the bath to a temperature below 40xc2x0 C.; washing the dyed fibers or fabrics in clean water at a temperature between 25 to 40xc2x0 C. to wash off loose color after the residual liquor in the bath has been discharged; and
3) drying the fibers or fabrics.
The following is the detailed method of dyeing the animal hair fibers or the blended yarn or their fabrics according to the present invention:
Pre-treating: The fibers or fabrics, treated with detergents, are fixed into a dyeing machine, then water at a temperature of 20xcx9c30xc2x0 C. is added and circulated with a pump. The bath ratio (the weight ratio of the fiber or fabric to water) is between 1:30 and 1:50. The pH value of the bath is adjusted to 3xcx9c6 with the addition of acids, then the compound of formula [1] as a cationic dyeing auxiliary agent as a solution in water is added in an amount of 1xcx9c8 wt. % on the basis of the total weight of the fibers or fabrics, then the bath is circulated with a pump for 15xcx9c20 minutes.
Dyeing: Formulated cationic dyes are introduced into the bath in an amount of 0.01xcx9c2 wt. % and 0.01xcx9c3 wt. % on the basis of the fibers or fabrics for dyeing animal hair fiber or its fabrics and for dyeing blended yarn or fabrics containing animal hair fiber, respectively. After cycling the bath with a pump for 10xcx9c15 minutes at ambient temperature, preferably 25xcx9c28xc2x0 C., the bath is warmed to 98xcx9c100xc2x0 C. at a rate of 12xc2x0 C./min, then boiled for 40xcx9c60 minutes at that temperature. The bath is then cooled to a temperature below 40xc2x0 C. The dyed fibers or fabrics are washed by clean water at a temperature between 20 to 40xc2x0 C. to wash off loose color two or three times after the residual liquor in the bath has been discharged. Then the dyeing step is complete.
The so-called drying step is when the fibers or fabrics are hydro-extracted and oven-dried.
In the pre-treating step, it is preferred to use weak acid to adjust the bath to a weak acid state. Furthermore, considering device corrosion and environmental pollution, acetic acid is most preferred.
When used as a cationic dye auxiliary agent for dyeing and finishing such animal protein fibers as wool and fabrics with cationic dyes, the compound as formula [1] according to the present invention plays a key role, and its amount directly influences the results of dyeing and finishing. It is discovered that if the amount of compound [1] is too small, the rate of dyeing and dyeing quality cannot meet the requirement. But if the amount is too big, the compound as formula [1] and the cation from the cationic dyes will form precipitates which deposit on the surface of protein fibers; consequently, the dyeing performance is adversely affected. Experiments show that when the amount of fibers and dyes and other conditions remain unchanged, the smaller the amount of compound [1] used, the lighter the depth of shade the product has; on the contrary, the larger amount of compound [1] used, the deeper the depth of shade the product has.
In general, the amount of compound [1] is limited between 1 and 8% by weight, based on the weight of the fabric substrate. When dyeing and finishing the fibers with light color, the amount is limited between 1 and 3% by weight; and for the fibers with medium heavy color, the amount is in the range of 5 to 8% by weight.
In addition, the control of pH value in the dyeing and finishing process has a great effect on the texture, glossiness and color stability of the dyed fibers. With a lower pH value, the fibers are accompanied with quickly dyed and high dye takeup, but the strength criteria is lower and uneven dyeing more likely. When the pH value is higher, the fibers will have good strength properties, but a low rate of dyeing and poor brightness. Therefore, for wool, cony hair, cashmere, camel""s hair and other fibers, the pH value is preferably selected from a range of 3 to 8.
Before dyeing and finishing such animal protein fibers as wool and fabrics by use of the compound [1] as a cationic dye auxiliary agent, the compound [1] is first dissolved in water at a temperature between 30 and 60xc2x0 C., with concentration of the solution based on its saturated solution.
The experimental results show that use of the compound [1] of the invention as cationic dye auxiliary agents overcomes the prior difficulties encountered when using cationic dyes for dyeing and finishing such animal protein fibers as wool. And, for blended yarn or fabrics containing animal protein fibers, the stage-dyeing process is no longer necessary. The present invention simplifies the whole dyeing and finishing process, and results in a good dyeing quality. It is also discovered that if the dye depth is the same, the process according to the present invention can reduce the consumption of dyes and thus improve the economic benefits. Furthermore, owing to the fact that in the dyeing and finishing process addition of other auxiliary agents, such as mordant, softeners, diffusing agents, penetrant, and so on, are not needed, environmental pollution caused by discharge of waste liquids is substantially reduced.
The present invention further provides a method for dyeing and finishing natural silk by cationic dyes by using the cationic dye auxiliary agents according to the present invention. The method also includes three processes:
1) circulating the bath which contains fibers or fabrics with water at a temperature of 20xcx9c25xc2x0 C. for 10 to 15 minutes, in which the bath ratio is 1:30 to 1:50, and the pH value is adjusted into a range of 4 to 8; adding the compound [1] into the bath in an amount of 1xcx9c8 wt. % on the basis of the total weight of the fibers or fabrics; then circulating the solution for 15xcx9c20 minutes;
2) adding cationic dyes into the bath in an amount of 0.01xcx9c3% by weight on the basis of the total weight of the fiber or the fabrics; after cycling the bath for 15xcx9c20 minutes at ambient temperature, heating the bath to 75xcx9c85xc2x0 C. at a rate of 12xc2x0 C./min, then sustaining the bath at this temperature for 10xcx9c30 minutes; heating the bath to 98xcx9c100xc2x0 C. at a rate of 2xcx9c3xc2x0 C./min, and sustaining it at this temperature for 30xcx9c50 minutes, cooling the bath to a temperature below 40xc2x0 C.; washing the dyed fibers or fabrics by clean water at a temperature between 20 to 35xc2x0 C. to wash off loose color after the residual liquor in the bath has been discharged; and
3) drying the fibers or fabrics.
In particular, the three steps are:
Pre-treating process: The fibers or fabrics, fine-worsted in advance and treated with detergents, are fixed into a dyeing machine and then washed two to four times with water at a temperature of 20xcx9c25xc2x0 C. for about 10xcx9c15 minutes. The bath ratio (weight ratio of the fibers or fabrics to water) is 1:30 to 1:50; pH value is adjusted into a range of 4 to 8 with addition of acids, preferably a weak acid, most preferably acetic acid. A solution of the dissolved compounds [1] (which is dissolved in water at a temperature between 30 and 60xc2x0 C., with concentration of the solution based on its saturated solution) is added in an amount of 1xcx9c8 wt. % on the basis of the fibers or fabrics. Then the solution is circulated with a pump for 15xcx9c20 minutes.
Dyeing: Cationic dyes formulated in an amount of 0.01xcx9c3%, based on the weight of the fiber or the fabrics is added into the dye vessel. After cycling the bath with a pump for 15xcx9c20 minutes at ambient temperature, preferably 20xcx9c25xc2x0 C., the bath is warmed to 75xcx9c85xc2x0 C. at a rate of 1xcx9c2xc2x0 C./min, then sustained at this temperature for 20xcx9c40 minutes. Then the bath is warmed to 98xcx9c100xc2x0 C. at a rate of 2xcx9c3xc2x0 C./min, and sustained at this temperature for 30xcx9c50 minutes. The bath is cooled to a temperature below 40xc2x0 C. The dyed fibers or fabrics are washed by clean water at a temperature between 20 to 35xc2x0 C. to wash off loose color two or three times after the residual liquor in the bath has been discharged.
Drying: The fibers or fabrics are hydro-extracted and oven-dried.
The amounts of the compound [1] are also a key factor which affects the dyeing quality. If the amount is too small, the rate of dyeing is low and the dyeing quality cannot meet the requirements. But if the amount is too big, the compound [1] and the cation from the cationic dyes will form precipitates which deposit on the surface of protein fibers. Consequently, the dyeing performance will be adversely affected.
It is shown that, when dyeing and finishing natural silk and fabrics therefrom with light color, the amount of the compound [1] used as a cationic dye auxiliary agent in the present invention is limited between 1 and 3% by weight on the basis of the fibers or fabrics. And for natural silk and fabrics with medium heavy color, the amount is in the range of 3 to 5% by weight. For natural silk and fabrics with heavy color, the amount is in the range of 5 to 8% by weight.
Due to the use of the cationic dye auxiliary agent, it is possible to dye and finish the natural silk and its fabrics with cationic dyes and to obtain good dyeing quality, high color fastness and bright color. Furthermore, the dyeing process doesn""t discharge strong acid and hypertoxic residual liquor, thus environmental pollution is substantially reduced, owing to the fact that no additional auxiliary agents, such as mordant, softeners, diffusing agents, penetrant, fixing agents (particularly such hypertoxic chemicals as NaCN), are needed in the process.
At the same time, great improvements have been made for dyeing and finishing blended yarn and blended fabrics (such as the mixture of hairs and synthetic fibers, e.g., acrylic fiber, as well as the mixture of natural silk and rayon) which can be dyed by a one-step process. On the contrary, owing to the use of different types of dyestuffs, a two-step process is needed in the prior art. For the cationic dye auxiliary agents of the present invention, the advantages for dyeing and finishing blended fibers or textiles thereof are significant, such as time saved for dyeing and finishing, reduced amounts of dyes, and shortening processing procedures, so costs are decreased to a great extent. Therefore, the above methods of dyeing and finishing hair fibers or fabrics provided by the present invention may be extended to blended fibers or fabrics. Examples will be given to illustrate the effectiveness for dyeing blended yards (e.g., acrylic fiberxe2x80x94wool with different wool content) and mixed shameuse (natural silk and rayon).